Latch mechanism



April 1963 I E. L. MACOICZ 3,377,093

LATCH MECHANIS M Filed April 26, 1966 2 Sheets-Sheet l IN VENTOR EDWARD L. MACOICZ |e.2 BY Q W ATT'Y.

E. L. MACOICZ April 9,1968

LATCH MECHANISM 2 Sheets-Sheet 2 Filed April 26, 1966 INVENTOR EDWARD L, MA 00102 ATT'X United States Patent 3,377,093 LATCH MECHANISM Edward L. Macoicz, Shorewood, Wis., assignor to General Electric Company, a corporation of New York Filed Apr. 26, 1966, Ser. No. 545,430 4 Claims. (Cl. 292-241) ABSTRACT OF THE DISCLOSURE A combination latching mechanism and switch actuating device for the cabinet door of an electrical appliance, such as a dishwasher or the like. A bolt mechanism is mounted on a support structure carried by the door for movement into and out of latching engagement with a strike mounted on the cabinet. A normally-open electric switch is mounted in a fixed relation relative to the bolt mechanism and a switch actuator is disposed in the path of movement of the bolt mechanism for actuation of the switch to closed circuit condition upon movement of the bolt mechanism in a latching direction and return of the switch to an open position upon return movement of the bolt mechanism. A look out device is mounted on the bolt mechanism for transverse movement relative thereto between a first position in which it engages both the support structure and the bolt mechanism to prevent movement of the bolt mechanism in a latching direction, and a second position wherein the lock out device disengages the support structure thereby releases the bolt mechanism for movement in a latching direction. Means are provided for moving the lock out device into the first position unless it is firmly engaged with the strike.

This invention relates to apparatus in which an electrical switch is to be operated by means of a latch arranged to secure a cabinet door or other closure in a tightly closed position, and it is a particular object of the invention to provide means which will prevent operation of the switch until the cabinet door attains a pre-determined position relative to the cabinet.

Although not limited thereto, my invention is particularly applicable for use in automatic dishwashers. In the dishwasher, a normally open, door-latch operated switch is in series electrical circuit with the electrically actuated timing devices which automatically conduct the dishwasher through a pre-determined series of operations which include various washing and rinsing steps. It is frequently the case that after the dishwasher is placed in operation, the operator wishes to add a dish or utensil which she had forgotten to place in the dishwasher, and the door-latch operated switch will break the energizing circuit when the latch is operated to permit the door to be opened. The obvious purpose of this is to prevent the operation of the dishwasher when the door is even in an ajar position; for as well known in the art, dishwashers operate on the principle of subjecting the dishes to the action of sprays or streams of washing liquid, and such liquid would splash out of an even partly open door if the operation of the pump or impeller were not interrupted in advance of opening the door.

It is, therefore, an object of my invention to provide an improved and simplified switch-operating latching mechanism for the door of a cabinet, in which the switch assumes an open circuit condition when the latch is oper ated in an unlatching direction, and the latching mechanism is automatically locked against movement in its latching direction when the door is moved away from its closed position.

In a presently preferred embodiment of my invention, a combination latching mechanism and switch actuating device is provided for a cabinet having a door movable to a closed position therewith. A latch strike is mounted on the cabinet and a cooperating bolt mechanism is mounted on support structure in the door, the bolt mechanism being supported for movement into or out of latching engagement with the strike. Mounted in fixed relation to the bolt mechanism is a normally open electric switch; a switch actuator is disposed in the path of movement of the bolt mechanism for actuation of the switch to a closed circuit condition upon movement of the bolt mechanism in a latching direction and return of the switch to the open position upon return movement of the bolt mechanism.

Mounted on the bolt mechanism and movable relative thereto is a lock-out device, operable between a first position engaging both the support structure and the bolt mechanism to prevent movement of the bolt mechanism in a latching direction, and a second position wherein the lockout device disengages the support structure and thereby releases the bolt mechanism and lock-out device for movement in the latching direction. Means are provided to operate the lock-out device to its second position upon closing the door against the cabinet, whereby the bolt mechanism may be operated in the latching direction. Also included are means for automatically moving the lock-out device into engagement with the support structure upon withdrawal of the door from the closed position, whereby the lock-out device secures the bolt mechanism against operation in the latching direction and thereby precludes closing of the electric switch while the door is open.

Other advantages of my invention will be apparent from the following detailed description of a presently preferred embodiment thereof, read in connection with the accompanying drawings in which:

FIGURE 1 is a fragmentary sectional elevation of the upper front portion of a dishwasher door and cabinet, showing the door in the fully closed, and latched, position;

FIGURE 2 is an enlarged top plan view of the latch and strike assembly with the latch lever in its latched position and the lock-out device in its inoperative position;

FIGURE 3 is a top plan view of the latch with the latch lever in its unlatched position and the lock-out device in its engaged, or operative position, with the door partly open;

FIGURE 4 is a sectional view taken along the line 44 of FIGURE 3, illustrating the latch strike and lock-out device in greater detail;

FIGURE 5 is a top plan view of the latch mounting bracket showing the details thereof; and

FIGURE 6 is a view similar to FIGURE 3 and shows the position of the lock-out device in its disengaged position when the door is closed but not latched.

Referring now to the drawings, and more particularly to FIGURE 1 thereof, the upper front portion of a dishwasher tub V1 is illustrated in its usual environment below a kitchen counter 2. The dishwasher door 3 is in the fully closed position, with the rim 4 of the door engaging the peripheral gasket 5 about the rim of the tub to effect a tight seal to protect against leakage of liquid when the dishwasher is in operation. The dishwasher tub has a plate 6 secured thereto for adjustable forward projection therefrom. The plate 6 includes a downwardly depending strike 7 at the front end thereof. A roller 8 (FIGURE 4) is rotatably secured about strike 7 to reduce the frictional force between the strike and the bolt when the bolt is rotated thereabout.

The cooperating bolt mechanism is indicated generally by numeral 9, and, as shown in FIGURES 1 and 4, includes an inverted, L-shaped mounting bracket 10 by means of which the bolt mechanism -9 is supported within door 3. Bracket 16 is secured to the underside of the top transverse portion of door 3 by screws 11 which pass through the rim of the door and into suitable threaded openings in the top of the bracket.

A latch pin 12 extends upwardly through a suitable opening 12A (FIGURE 5) in the top of mounting bracket 10, and it will be understood that the relative dimensions of opening 12A and pin 12 are such as to permit rotation of the pin within the opening. A latch plate 13 is mounted for rotational movement relative to bracket by rigidly securing the latch plate to pin 12. Latch plate 13 includes an outwardly extending lever arm 14, by means of which the latch plate 13 is caused to rotate, with a concurrent rotation of pin 12. Extending upwardly at the front of latch plate 13 is a flange or tongue 16 which serves as the bolt for the mechanism. As will be observed from FIGURES 2, 3, and 6, the bolt 16 has a first spirally formed section 16.1, and terminates in a second arcuate portion 16.2. When the door is fully closed, strike 7 with roller 8 is adapted to extend immediately beyond the bolt 16 as shown in FIGURE 6. As the lever arm 14 is rotated in the counter clock-wise direction, from the position shown in FIGURE 6 to that shown in FIGURE 2, the spiral portion 16.1 of the bolt 16 engages roller 8 and draws the door 3 into a tightly closed position with the dishwasher.

As the lever arm progresses toward the position shown in FIGURE 2, roller 8 passes over the juncture formed by the intersection of the two curved portions 16.1 and 16.2, and, when fully latched, resides within the arcuate portion 16.2 of the latch bolt. When the door is tightly closed during operation of the dishwasher, both the gasket 5, which is under compression, and the water pressure within the wash chamber tend to force the door outwardly. If the roller 8 resided in the spiral portion, the aforementioned forces acting on the door might cause the latch plate to rotate to the open position, thereby allowing the door to open slightly with the possibility of escape of water onto the floor. The juncture of the two curved surfaces therefore provides sufiicient locking action to preclude the roller 8 from passing onto the spiral section 16.1 during normal operation.

As will be observed from FIGURE 1, lever arm 14 is actually disposed in a plane below the plane of the latch plate 13, the two sections being joined by short vertical portion 14.1 of the lever arm. The vertical section 14.1 engages the mounting bracket 10 as the lever arm is rotated between the open and closed positions, and thereby prevents the lever arm from passing over the mounting bracket in such a manner as to inoperatively dispose the bolt. Secured between the vertical portion 14.1 and the downwardly extending leg 10A of the mounting bracket is a tension spring 17 which maintains the lever arm 14 in the open or closed position.

Disposed on latch pin 12 below mounting bracket 10 is a cam 18, which is adapted to rotate with lever arm 14. Cam 18 has two outwardly extending ears, 19 and 20, which extend beyond the vertical portion 14.1 of the lever arm, so that upon rotation of the lever arm in either direction, vertical portion 14.1 thereof will engage either ear 19 or 20 of the cam and cause it to rotate therewith. While the cam may be fixedly secured to pin 12, the extended ears thereon insure a positive rotation of the cam with the lever arm.

A switch 21 is mounted on the downwardly extending leg 10A of the mounting bracket 10, and is provided with an actuating push button 22 disposed in the path of movement of the cam 18. When the lever arm 14 is ro- -tated counter clock-wise in FIGURE 6, the cam rotates through a 120 arc. The cam engages the switch button after rotating 24, and the switch is depressed by operation of the cam at about the 60 midpoint, illustrated by reference point 18.1 in FIGURE 1. In a dishwasher or similar appliance in which switch 21 is a normally open switch in series with the main power circuit (not shown), the actuation of the switch to closed circuit condition is coincident with the latching engagement of the bolt with the strike roller 8, thereby insuring that the dishwasher will not be operated until the door 3 is fully closed. It is, of course, possible that some conditions of operation will require that the switch 21 be in the normally closed position, whereupon the operation of the cam 18, as described above, will open the switch circuit.

To prevent closing of the switch when the door is in an open position, I have provided the lock-out mechanism illustrated generally by numeral 23, which prevents rotation of the lever arm 14, and, accordingly, cam surface 18, when the dishwasher door is even partially open.

Referring now to FIGURE 5, it will be observed that the mounting bracket 10 includes a generally semi-circular slot 24 therethrough. The end of the slot closest to rim 4 includes a forwardly extending pocket or notch 25 therein. Secured above latch plate 13 is the lock-out or detent mechanism. The lock-out device 23 has an elongated slot 26 therethrough which permits both rotational and transverse movement of the lock-out device with respect to pin 12. A washer 26A is disposed on pin 12 over lock-out device 23 to maintain the members in proper vertical alignment.

The front end of the lock-out mechanism includes an upwardly extending semi-circular car 27, which, when the door is open, is disposed in the path of strike 7, as best shown in FIGURE 3. The lock-out device includes a downwardly extending finger 28 (FIGURE 4) which passes through a suitable aperture 29 in the latch plate, and resides in the slot 24 of mounting bracket 10. Aperture 29 is coextensive with pocket 25 of slot 24 when the latch plate is in the unlatched position, so that finger 28 can move into the pocket when the lock-out device is properly positioned. At the rear of the detent mechanism and opposite car 27 is an upwardly extending finger 30. A coil spring 31 is secured between the upwardly extending finger 30 and latch pin 12, the spring normally biasing the lock-out 23 to a forward position, pursuant to which the downwardly extending finger 28 of the lock-out engages within the forwardly extending pocket 25 of slot 24 when the lever arm is in the position shown in FIGURE 3. When the lock-out device is in this position, it is impossible to rotate the lever arm to the closed position.

Upon closing the door, the roller 8 engages ear 27 of the lock-out device and moves it to the position shown in FIGURE 6. The respective elements are so related that when the door is closed sufficiently for the roller 8 to engage behind the spiral portion 16.1 of the bolt, the lockout device 23 is moved to its disengaged or inoperative position, with the finger 28 extending into the curved portion of slot 24, whereupon the lever arm 14 may be rotated to complete the latching of the door and the cam 18 will actuate the switch button as heretofore described. As the lever arm is rotated, the action of latch plate 13 on finger 28 causes the lock-out device to rotate therewith, and finger 28 will move freely through the arcuate slot 24 to the position shown in FIGURE 2.

It will be observed that in order to open the dishwasher, the latch plate and lever are rotated to the position shown in FIGURE 6. During rotation, cam surface 18 will disengage from switch 21, at about the midpoint of the latch plates rotational travel, whereby the switch will be in the open position and terminate operation of the dishwasher before the bolt has disengaged the strike. As soon as the door is even partially open, the force of spring 31 on lock-out device 23 causes it to shift forwardly, to the position shown in FIGURE 3, whereupon finger 28 will now extend into the pocket portion 25 of the slot and thereby prevent rotation of lever arm 14 to the closed position. Spring 31 is thus always in the extended position and ready to move the lock-out device into cooperating relation with the pocket upon rotation of the handle in the unlatching direction and the subsequent opening of the door.

Pursuant to my invention, I have provided a lock-out device which is mounted on the lever operated bolt and shifts to its operative position to engage with the bolt support structure immediately upon movement of the door in an opening direction, thereby securing the bolt against an operation which would actuate the switch to a closed circuit position. The lock-out device remains effective until the door obtains its closed position, whereupon the strike shifts the lock-out device to an inoperative position and thereby permits rotation of the bolt to secure the door and actuate the switch to the closed circuit position.

While there has been described What is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the scope of the invention.

I claim:

1. A combination latching mechanism and switch actuating device for a cabinet having a door movable to a closed position therewith, a latch strike mounted on said cabinet and a bolt mechanism mounted on said door, including:

(a) structure for supporting said bolt mechanism for movement into or out of latching engagement with said strike;

(b) means for operating said bolt mechanism in a desired direction;

(c) a normally open electric switch mounted in fixed relation to said bolt mechanism;

((1) a switch actuator disposed in the path of movement of said bolt mechanism for actuation of said switch to closed circuit condition upon movement of said bolt mechanism in a latching direction and return of said switch to open position upon return movement of said bolt mechanism;

(e) a lock-out device mounted on said bolt mechanism for transverse movement relative thereto across said path of movement between a first position wherein said device engages both said support structure and said bolt mechanism to prevent movement of said bolt mechanism in a latching direction, and a second position wherein said lock-out device disengages said support structure and thereby releases said bolt mechanism for movement in said latching direction;

.(f) said strike being effective upon closing said door against said cabinet to move said lock-out device to its second position whereby said bolt mechanism may be operated in the latching direction; and

(g) means for automatically moving said lock-out device into engagement with said support structure upon withdrawal of said door from a closed position, whereby said lock-out device secures said bolt mechanism against operation in the latching direction and thereby precludes closing of said switch while said door is open.

2. The combination according to claim 1 wherein:

(a) said support structure has an arcuately shaped slot therethrough, said slot terminating in a notch extending toward said strike when said door is closed;

(b) said bolt mechanism includes a latch plate rotatably disposed on said support structure, said latch plate having bolt means extending upwardly therefrom for engagement with said strike;

(0) said latch plate has an aperture therethrough substantially equal in size to said notch in said support structure;

(d) said lock-out device is disposed over said latch plate, and includes a finger extending downwardly therefrom through said aperture and into said notch when said lock-out device is in said first position, whereby said finger engages said support plate at said notch and said latch plate at the aperture therethrough to thereby prevent rotation of said latch plate and said bolt; and

(e) said lock-out device is movable transversely over said latch plate to its second position upon engagement with said strike when said door is closed, whereupon said finger shifts within said aperture in said latch plate to said arcuate portion of said slot and thereby disengages from said support plate to permit rotation of said latch plate in the latching direction, the action of said latch plate on the finger of said lock-out device being effective to rotate said lock-out device therewith, said finger of said lock-out being movable within said arcuate slot of said support plate upon rotation of said lock-out device.

3. The combination according to claim 2 wherein said lock-out device further includes an upwardly extending ear thereon disposed above said finger, whereby when said lock-out device is in said first position with said finger engaging said support structure, said ear of said lock-out device is disposed for engagement with said strike upon closing of said door.

4. The combination according to claim 2 wherein:

(a) said upwardly extending bolt means includes a first spirally formed portion adapted to rotate about said strike when said door is closed, said spiral portion drawing said door into a tightly closed position;

(b) said bolt means terminating in a second arcuately formed portion wherein said strike resides when said latch plate is rotated to the fully latched position; and

(c) the intersection of said spiral portion and said arcuate portion extending toward said strike to provide a locking surface for said strike which prevents said strike from moving into said spiral portion when said roller is in the arcuate portion and said lever arm is in the fully latched position.

E. MOORE, Primary Examiner.

RICHARD 

